Light emitting device and method of manufacturing light emitting device

ABSTRACT

A light emitting device includes: a substrate including a grooved part surrounding a first region; a light emitting element mounted in the first region; a first cover member comprising: a reflecting material-containing layer that is disposed in the groove of the grooved part and that contains a first reflecting material, and a light transmitting layer that covers at least a portion of lateral surfaces of the light emitting element; and a light transmitting member disposed on the first cover member and the light emitting element.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2018-248307, filed on Dec. 28, 2018, the disclosure of which is herebyincorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a light emitting device and a methodof manufacturing the same.

A light emitting device having a light emitting element mounted on asubstrate has been known. For example, Japanese Patent Publication No.2017-204623 discloses a light emitting device that includes: a packagehaving a recessed part defined by lateral surfaces and a bottom surfaceand including a linear or dotted grooved part surrounding an elementmounting region provided in the bottom surface, spaced apart from thelateral surfaces; a light emitting element mounted in the elementmounting region; a light transmitting resin covering the light emittingelement and being in contact with the inner surface of the grooved part;and a light reflecting resin continuously formed from the lateralsurfaces of the recessed part to the upper edge of the outer perimeterof the grooved part.

SUMMARY

The technology disclosed in the patent publication mentioned above hasroom for improvement in efficiency of the light emission.

One object of the present disclosure is to provide a light emittingdevice having high light emission efficiency and a method ofmanufacturing light emitting device.

A light emitting device according to certain embodiment of the presentdisclosure includes: a substrate including a grooved part surrounding afirst region; a light emitting element mounted in the first region; afirst cover member disposed in a groove of the grooved part and coveringat least a portion of the lateral surfaces of the light emittingelement; and a light transmitting member disposed on the first covermember and the light emitting element. The first cover member includes areflecting material-containing layer containing a first reflectingmaterial disposed in the groove of the grooved part, and a lighttransmitting layer covering at least a portion of the lateral surfacesof the light emitting element.

A method of manufacturing a light emitting device according to certainembodiment of the present disclosure includes: providing a substratethat includes a grooved part surrounding a first region; mounting alight emitting element in the first region; forming a first resin in agroove of the grooved part, the first resin containing a firstreflecting material; forming a first cover member that include areflecting material-containing layer and a light transmitting layer byapplying centrifugal force, the reflecting material-containing layerformed in the groove of the grooved part being obtained by settling afirst reflecting material in a first resin, and the light transmittinglayer covering at least a portion of lateral surfaces of the lightemitting element; forming a light transmitting member on the first covermember and the light emitting element.

A light emitting device according to certain embodiment of the presentdisclosure can increase the light emission efficiency.

A method of manufacturing a light emitting device according to certainembodiment of the present disclosure may manufacture a light emittingdevice having high light emission efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic perspective view of a light emitting deviceaccording to certain embodiment.

FIG. 1B is a schematic top view of the light emitting device accordingto the embodiment, in which certain concealed parts are made visible.

FIG. 1C is a schematic cross-sectional view taken along line IC-IC inFIG. 1A.

FIG. 2 is a flowchart of a method of manufacturing a light emittingdevice according to an embodiment.

FIG. 3A is a schematic cross-sectional view showing a process ofmounting a light emitting element in the method of manufacturing a lightemitting device according to the embodiment.

FIG. 3B is a schematic cross-sectional view showing a process of forminga second cover member in the method of manufacturing a light emittingdevice according to the embodiment.

FIG. 3C is a schematic cross-sectional view showing a process of forminga first resin in the method of manufacturing a light emitting deviceaccording to the embodiment.

FIG. 3D is a schematic diagram showing a process of forming a firstcover member by allowing the first reflecting material to settle undercentrifugal force in the method of manufacturing a light emitting deviceaccording to the embodiment.

FIG. 3E is a schematic cross-sectional view of a process of forming afirst cover member in the method of manufacturing a light emittingdevice according to the embodiment, showing the state after settling thefirst reflecting material by centrifugal force.

FIG. 3F is a schematic cross-sectional view showing a process of forminga light transmitting member in the method of manufacturing a lightemitting device according to the embodiment.

FIG. 4 is a schematic cross-sectional view of a light emitting deviceaccording to another embodiment.

FIG. 5A is a schematic top view of the grooved part of a light emittingdevice according to another embodiment.

FIG. 5B is a schematic top view of the grooved part of a light emittingdevice according to another embodiment.

FIG. 5C is a schematic top view of the grooved part of a light emittingdevice according to another embodiment.

FIG. 6 shows images of the structures of the light emitting devices usedin Example 1.

FIG. 7A is a graph showing the relationship between the coating amountof the first resin and the luminous flux in Example 1.

FIG. 7B is a graph showing x chromaticity coordinate deviations atcertain directivity angles in Example 1.

FIG. 7C is a graph showing y chromaticity coordinate deviations atcertain directivity angles in Example 1.

FIG. 7D is a graph showing x chromaticity coordinate deviations atcertain directivity angles in Example 1.

FIG. 7E is a graph showing y chromaticity coordinate deviations atcertain directivity angles in Example 1.

FIG. 8A is an image of the light emitting device of Example 2 showingthe state after mounting a light emitting element and applying a secondresin.

FIG. 8B is an image of the light emitting device of Example 2 showingthe state after applying a first resin.

FIG. 8C is an image of the light emitting device of Example 2 showingthe state after settling the reflecting material by applying centrifugalforce to the first resin.

FIG. 8D is an image of the element's electrodes in the light emittingdevice of Example 2.

FIG. 8E is an image of the light emitting device of Example 2 showingthe state after forming a light transmitting member.

FIG. 9A is a graph showing the relationship between the chromaticitycoordinate and the luminous flux in Example 2.

FIG. 9B is a graph showing the luminous flux of each sample in Example2.

DESCRIPTION

Certain embodiments of the present invention will be explained belowwith reference to the drawings. The light emitting devices and themethods for manufacturing light emitting devices described below areprovided as examples to give shape to the technical ideas of the presentinvention. The present invention is not intended to be limited to theembodiments described below. The sizes, materials, shapes, and relativepositions of the constituent elements and parts described in eachembodiment are merely provided for illustration purposes, and are notintended to limit the scope of the present invention unless otherwisespecifically noted. The sizes of and the positional relationship betweenthe members shown in each drawing might be exaggerated for clarity ofexplanation.

Embodiments

Light Emitting Device

FIG. 1A is a schematic perspective view of a light emitting deviceaccording to certain embodiment. FIG. 1B is a schematic top view of thelight emitting device, in which certain parts are made visible. FIG. 1Cis a cross-sectional view taken along line IC-IC in FIG. 1A.

The light emitting device 100 includes a substrate 2 having a groovedpart 17 that surrounds a first region, a light emitting element 20mounted in the first region, a first cover member 30 disposed in thegroove of the grooved part 17 and covering at least a portion of thelateral surfaces of the light emitting element 20, and a lighttransmitting member 50 disposed on the first cover member 30 and thelight emitting element 20. In the light emitting device 100,furthermore, the first cover member 30 includes a reflectingmaterial-containing layer 30 a containing a first reflecting materialdisposed in the groove of the grooved part 17 and a light transmittinglayer 30 b covering at least a portion of the lateral surfaces of thelight emitting element 20.

In other words, the light emitting device 100 comprises: a package 10that includes a substrate 2; a light emitting element 20; a first covermember 30; a second cover member 40; and a light transmitting member 50.

Each constituent element of the light emitting device 100 will beexplained below.

The package 10 has a recessed part 15 structured with a bottom surfacecomposed of the substrate 2 and lateral surfaces composed of resin walls3. The opening of the recessed part 15 is, for example, substantiallyquadrilateral having a corner shaped different from the other corners ina top view.

The substrate 2 includes a pair of lead electrodes configured as a firstlead electrode 2 a and a second lead electrode 2 b, and a resin moldedpart 2 c that supports the first lead electrode 2 a and the second leadelectrode 2 b.

The first lead electrode 2 a is exposed at the bottom surface of therecessed part 15 and connected to the light emitting element 20 and awire 23. The second lead electrode 2 b is exposed at the bottom surfaceof the recessed part 15 and connected to a wire 24.

The first lead electrode 2 a has a grooved part 17 that surrounds afirst region 16 where a light emitting element 20 is mounted. Thegrooved part 17 here is formed such that the parts immediately under thelateral surfaces of the light emitting element 20 are positioned atupper edge of the inner perimeter the grooved part 17. In other words,the grooved part 17 is formed along the outer lateral surfaces of thelight emitting element 20. The grooved part 17 here has a square annularshape in a top view to surround the first region 16. However, thegrooved part 17 can surround the region in another shape, such as anannular or diamond annular shape.

The width of the grooved part 17 surrounding the first region can besubstantially the same over the entire perimeter, or can differ insections. The width of the grooved part 17 is preferably in a range of30 μm to 200 μm. The grooved part 17 having a width of 30 μm or largercan make it easy to contain the reflecting material-containing layer 30a described later in the groove of the grooved part 17. The grooved part17 having a width of 200 μm at most can reduce the amount of the firstcover member 30. The grooved part 17 having a width of 200 μm at mostcan enhance the strength of the substrate 2 as well.

The depth of the grooved part 17 is preferably in a range of 10 μm to150 μm. The grooved part 17 having a depth of at least 10 μm can make iteasy to contain the reflecting material-containing layer 30 a describedlater in the groove of the grooved part 17. The grooved part 17 having adepth of at least 10 μm can also facilitate settling of the firstreflecting material. The grooved part 17 having a depth of 150 μm atmost can reduce the amount of the first cover member 30.

The grooved part 17 is preferably disposed adjacent to the lightemitting element 20. Specifically, the grooved part 17 is preferablyformed in the position of no more than 100 μm apart from the lateralsurfaces of the light emitting element 20. In other words, the groovedpart is formed such that the distance between the lateral surfaces ofthe light emitting element 20 and the upper edge of the inner perimeterof the grooved part 17 is 100 μm at most. Such a distance from the lightemitting element 20 of 100 μm at most can facilitate reflection of thelight from the light emitting element 20 by the reflectingmaterial-containing layer 30 a, thereby improving the light emissionefficiency. In order to further improve the light emission efficiency,the grooved part 17 is preferably formed closer to the light emittingelement 20, more preferably formed at the position that is 0 μm from thelight emitting element 20 such that the inner lateral surface of thegrooved part 17 is disposed along the outer lateral surfaces of thelight emitting element 20. As long as the upper edge of the outerperimeter of the grooved part 17 is positioned outward of the outeredges of the light emitting element 20 in a top view, the parts directlyunder the lateral surfaces of the light emitting element 20 can belocated above the grooved part 17. In this case, it is preferable to setthe distance between the lateral surfaces of the light emitting element20 and the upper edge of the inner perimeter of the grooved part 17 to50 μm at most, considering the mountability and the heat dissipation ofthe light emitting element 20.

For the first lead electrode 2 a and the second lead electrode 2 b, forexample, Fe, Cu, Ni, Al, Ag, Au, or an alloy including one of these, canbe used.

Surface plating can be applied to the first lead electrode 2 a and thesecond lead electrode 2 b. For example, Au, Ag, Cu, Pt, or an alloyincluding one of these can be used for plating. Using these materialsfor plating can further increase the reflectance for the light emittedfrom the light emitting element 20 towards the lead electrodes.

The resin walls 3 are formed in the edge portion of the upper surface ofthe substrate 2. The outer wall surfaces of the resin walls 3 are formedalong the outer lateral surfaces of the substrate 2. The inner wallsurfaces of the resin walls 3 are oblique such that the opening of therecessed part 15 becomes wider from the substrate 2 to its open end. Theresin walls 3 are also disposed in the groove formed at the uppersurface of the substrate 2, to thereby enhance the adhesion between theresin walls 3 and the substrate 2.

For the resin walls 3 and the resin molded part 2 c, for example,thermoplastic resins, such as PA (polyamide), PPA (polyphthalamide), PPS(polyphenylene sulfide), or liquid polymer, or thermosetting resins,such as epoxy resins, silicone resins, modified epoxy resins, urethaneresins, or phenol resins, can be used.

The resin walls 3 and the resin molded part 2 c can be integrally formedusing the same material.

The light emitting element 20 is a semiconductor element that itselfemits light when a voltage is applied. The light emitting element 20 inthe present embodiment includes a light transmissive support substrate21 and a semiconductor layer 22 formed on the support substrate 21.Besides an insulation material, a conductive material can be used forthe support substrate 21. Any shape, size, and the like can be selectedfor the light emitting element 20. For the emission color of the lightemitting element 20, one having any wavelength can be selected inaccordance with the application. For example, for the light emittingelement 20 emitting blue light (i.e., light having a wavelength in arange of 430 nm to 490 nm) or green light (i.e., light having awavelength in a range of 495 nm to 565 nm), one using a nitride-basedsemiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N, 0≤X, 0≤Y, X+Y≤1), GaP, or thelike can be employed. For the light emitting element 20 emitting redlight (i.e., light having a wavelength in a range of 610 nm to 700 nm),GaAlAs, AlInGaP, or the like, besides a nitride-based semiconductorelement, can be employed.

The thickness of the light emitting element 20 (i.e., from the lowersurface of the support substrate 21 to the upper surface of thesemiconductor layer 22) is set, for example, in a range of 100 μm to 300μm.

The light emitting element 20 includes a pair of electrodes on the uppersurface, and is mounted on the first lead electrode 2 a at the bottomsurface of the recessed part 15 of the package 10 with the electrodeside facing up. In the present embodiment, one of the electrodes of thelight emitting element 20 is connected to the first lead electrode 2 avia a conductive member such as a wire 23, and the other electrode isconnected to the second lead electrode 2 b via a conductive wire such asa wire 24.

Mounting the light emitting element 20 with the electrode side facing upallows the semiconductor layer 22 of the light emitting element 20 to beplaced on the upper surface side (i.e., the light extraction surfaceside of the light emitting device 100). In this manner, the lateralsurfaces of the semiconductor layer 22 is less likely to be covered bythe first cover member 30.

Such a structure can reduce the loss of primary light attributable toreflection by the lateral surfaces of the light emitting element 20.Moreover, the increased primary light extractable from the lateralsurfaces of the light emitting element 20 can further improve the lightdistribution characteristics of the light emitting device 100.

The first cover member 30 is formed in the groove of the grooved part17, and to cover some portions of the lateral surfaces of the lightemitting element 20. The first cover member 30 is formed with a firstresin that contains a first reflecting material. In the presentembodiment, the first cover member 30 is formed such that a firstreflecting material-containing layer 30 a and a light transmitting layer30 b containing substantially no first reflecting material are formed atthe grooved part 17 from the bottom side of the recessed part 15 in thatorder. The reflecting material-containing layer 30 a is disposed in thegroove of the grooved part 17. Disposing the reflectingmaterial-containing layer 30 a in the groove of the grooved part 17 caninhibit the first reflecting material-containing layer 30 a to face thelateral surfaces of the light emitting element 20 while facilitatingreflection of the light from the light emitting element 20, to therebyimprove the light emission efficiency.

The light transmitting layer 30 b is positioned above the reflectingmaterial-containing layer 30 a while covering some portions of thesecond cover member 40. The light transmitting layer 30 b covers someportions of the lateral surfaces of the light emitting element 20, butcan cover the lateral surfaces entirely.

The lateral surfaces of the light emitting element 20 in the presentembodiment include the lateral surfaces of the support substrate 21 andthe lateral surfaces of the semiconductor layer 22.

The reflecting material-containing layer 30 a is a layer created bysettling the first reflecting material, and is the portion of the firstcover member 30 that has a high concentration of the first reflectingmaterial in the depth direction. The light transmitting layer 30 b is alayer formed after the first reflecting material has been settled, andis primarily composed of a resin formed on the upper side. In otherwords, there is no clear interface between the reflectingmaterial-containing layer 30 a and the light transmitting layer 30 b.

The reflecting material-containing layer 30 a is preferably disposed soas not to cover the lateral surfaces of the light emitting element 20.This can increase the efficiency of extracting light from the lateralsurfaces of the light emitting element 20, thereby improving the lightdistribution characteristics in the lateral directions of the lightemitting element 20.

Examples of resin materials employed for the first resin includethermosetting resins, such as epoxy resins, modified epoxy resins,silicone resins, modified silicone resins, and the like.

The viscosity of the first resin is preferably in a range of 0.3 Pa·s to15 Pa·s at room temperature (20±5° C.). The first resin having aviscosity of at least 0.3 Pa·s can facilitate the application of thefirst resin at the bottom surface of the recessed part 15 by a pottingprocess. The first resin having a viscosity of 15 Pa·s at most canpromote changing a shape of the first cover member 30 under centrifugalforce. The first resin having a viscosity of 15 Pa·s at most can alsofacilitate settling of the first reflecting material under centrifugalforce. The preferable viscosity of the first resin for achieving theeffects described above is in a range of 0.5 Pa·s to 6 Pa·s.

The viscosity of the first resin here is the viscosity in the state ofcontaining the first reflecting material, and the state before settlingthe first reflecting material contained in the first resin bycentrifugal force as described later.

Examples of light reflecting materials employed as the first reflectingmaterial include titanium oxide, silica, silicon oxide, aluminum oxide,zirconium oxide, magnesium oxide, potassium titanate, zinc oxide, boronnitride, and the like. Among such examples, titanium oxide having arelatively high refractive index is preferable from a light reflectionperspective.

For the first reflecting material, one having a larger specific gravitythan the resin employed for the first resin is preferably used. Thespecific gravity difference between the first reflecting material andthe resin material can facilitate the settling of the first reflectingmaterial in the groove of the grooved part 17 under centrifugal force.Furthermore, using a material having a large particle diameter for thefirst reflecting material can more quickly settle the first reflectingmaterial in the groove of the grooved part 17.

The use of centrifugal force can dispose the first reflecting materialwith high density, which reduces the interparticle spacing, therebyreducing leakage or transmission of light and improving light reflectionby the first reflecting material-containing layer 30 a.

The particle diameter of the first reflecting material is preferably ina range of 0.1 μm to 1.0 μm. A particle diameter of at least 0.1 μm canfacilitate the settling of the first reflecting material undercentrifugal force. A particle diameter of 1.0 μm at most can facilitatethe reflection of visible light. From the above described perspective,the particle diameter of the first reflecting material is morepreferably in a range of 0.4 μm to 0.6 μm.

The second cover member 40 is a member for reflecting the emitted lightfrom the light emitting element 20.

The interior surface of the recessed part 15 except for the region wherethe grooved part 17 is present is preferably covered with the secondcover member 40 such that the light emitted by the light emittingelement 20 is not transmitted or absorbed by the bottom surface or thelateral surfaces of the recessed part 15.

The second cover member 40 is formed to cover the lateral surfaces ofthe recessed part 15 of the package 10. The second cover member 40continuously covers from the lateral surfaces of the recessed part 15 tothe upper edge of the outer perimeter of the grooved part 17. In otherwords, the second cover member 40 continuously covers from the upperedges of the lateral surfaces of the recessed part 15 to the upper edgeof the outer perimeter of the grooved part 17. The second cover member40 is formed by using a second resin that contains a second reflectingmaterial. The second cover member 40 more preferably covers the lateralsurfaces of the recessed part 15 across substantially entirely in theheight direction, but at a minimum condition, preferably covers theinner lateral surfaces of the recessed part 15 such that the upper edgesof the second cover member are higher than the upper surface of thelight emitting element in a cross-sectional view. The second covermember 40 is disposed from the inner wall surfaces of the resin walls 3to the region immediately before the grooved part 17. The second covermember 40 is formed such that the upper surface is covered by the lighttransmitting layer 30 b from the outer edge of the groove 17 to apredetermined position.

The second cover member 40 is a member in which the second reflectingmaterial is dispersed in the second resin. In the present embodiment,the second reflecting material being dispersed in the second resin meansthat the reflecting material is dispersed to sufficiently function as areflecting layer. For example, it suffices that the state of dispersionachieved in the case of applying a resin that contains a reflectingmaterial by a method known in the art. The second reflecting materialcan be partially localized in the second cover member 40 as long as thesecond cover member can function as a reflecting layer.

The concentration of the second reflecting material relative to thesecond cover member 40, for example, can be in a range of 10 masspercentage to 50 mass percentage.

Covering the bottom surface and the lateral surfaces of the recessedpart 15 with the second cover member 40 can inhibit light transmittanceor absorption at the bottom surface and the lateral surfaces of therecessed part 15.

Examples of resin materials employed for the second resin includethermosetting resins, such as epoxy resins, modified epoxy resins,silicone resins, modified silicone resins and the like. Examples oflight reflecting materials employed for the second reflecting materialinclude titanium oxide, silica, silicon oxide, aluminum oxide, zirconiumoxide, magnesium oxide, potassium titanate, zinc oxide, boron nitride,and the like. Among such examples, from a light reflection perspective,titanium oxide, which has a relatively high refractive index, ispreferably used.

The light transmitting member 50 is formed on the first cover member 30,the light emitting element 20, and the second cover member 40. The lighttransmitting member 50 is formed with a resin that transmits light.

Examples of resin materials employed for the light transmitting member50 include thermosetting resins, such as epoxy resins, modified epoxyresins, silicone resins, modified silicone resins, and the like. Theresin material used for the light transmitting member 50 can be the sameas or different from the resin material used for the first or secondresin described earlier. Alternatively, a hard resin can be employed forthe light transmitting member 50 while using a highly heat resistantresin for the first and second resins.

The first resin described earlier is preferably softer than the resinused for the light transmitting member 50. Because the first resin isdisposed in the vicinity of the bonding region between the lightemitting element 20 and the substrate 20, a material less likely toexpand by heat and having flexibility relative to heat is preferablyused so as not to cause excessive stress attributable to thermalexpansion.

Silicone resins generally have a higher light resistance than epoxyresins near 450 nm to 500 nm, and epoxy resins are harder than siliconeresins. Accordingly, a silicone resin can be used for the first andsecond resins, and an epoxy resin can be used for the light transmittingmember 50.

The light transmitting member 50 can contain a wavelength conversionmaterial. Examples of wavelength conversion materials include phosphors.The light transmitting member 50 can contain a diffuser, filler, or thelike, in accordance with the purpose.

For the phosphor, a phosphor known in the art can be used. Examples ofsuch phosphors include yellow light emitting phosphors, such as YAG(Y₃Al₅O₁₂:Ce) and silicate, red light emitting phosphors, such as CASN(CaAlSiN₃:Eu) and KSF (K₂SiF₆:Mn), or green light emitting phosphors,such as chlorosilicate and BaSiO₄:Eu²⁺.

For the diffuser, a diffuser known in the art can be used. For example,barium titanate, titanium oxide, aluminum oxide, silicon oxide, or thelike can be used.

Operation of Light Emitting Device

When the light emitting device 100 is activated, an electric current issupplied from an external power supply to the light emitting element 20via the first lead electrode 2 a and the second lead electrode 2 b toallow the light emitting element 20 to emit light. The light emitted bythe light emitting element 20 traveling upward is extracted upward ofthe light emitting device 100. The light emitted by the light emittingelement 20 traveling downward is reflected by the reflectingmaterial-containing layer 30 a and the second cover member 40 in thedirection towards the opening of the recessed part 15 to be extractedfrom the light emitting device 100 to the outside. The light emitted bythe light emitting element 20 laterally traveling is reflected by thesecond cover member 40 in the direction towards the opening of therecessed part 15 to be extracted from the light emitting device 100 tothe outside. This can reduce the leakage of the emitted light from thelight emitting elements 20 from the bottom surface and the lateralsurfaces of the recessed part 15, thereby increasing the lightextraction efficiency of the light emitting device 100. This also allowsthe light emitting device 100 to have less color non-uniformity. Withthe reflecting material-containing layer 30 a disposed in the groove ofthe grooved part 17, the light emitting device 100 can have improvedlight extraction efficiency and light emission efficiency.

Method of Manufacturing Light Emitting Device 100

One example of a method of manufacturing a light emitting deviceaccording to an embodiment of the present disclosure will be explainednext.

FIG. 2 is a flowchart of the method of manufacturing a light emittingdevice according to the embodiment. FIG. 3A is a cross-sectional viewshowing a process of mounting a light emitting element in the method ofmanufacturing a light emitting device according to the embodiment. FIG.3B is a cross-sectional view showing a process of forming a second covermember in the method of manufacturing a light emitting device accordingto the embodiment. FIG. 3C is a cross-sectional view showing a processof forming a first resin in the method of manufacturing a light emittingdevice according to the embodiment. FIG. 3D is a schematic diagram of aprocess of forming a first cover member in the method of manufacturing alight emitting device according to the embodiment, schematically showingthe process of settling the first reflecting material under centrifugalforce. FIG. 3E is a schematic cross-sectional view of a process offorming a first cover member in the method of manufacturing a lightemitting device according to the embodiment, showing the state aftersettling the first reflecting material by centrifugal force. FIG. 3F isa schematic cross-sectional view of a process of forming a lighttransmitting member in the method of manufacturing a light emittingdevice according to the embodiment.

The method of manufacturing a light emitting device 100 includes: asubstrate providing process S101 of providing a substrate 2 thatincludes a grooved part 17 surrounding a first region 16; a lightemitting element mounting process S102 of mounting a light emittingelement 20 in the first region 16; a second cover member forming processS103 of forming a second cover member 40 by allowing a second resin tocontinuously cover from the lateral surfaces of the recessed part 15 tothe upper edge of the outer perimeter of the grooved part 17; a firstresin forming process S104; a first resin depositing process S105 offorming a first resin in the groove of the grooved part 17, the firstresin containing a first reflecting material; a first cover memberforming process S106 of forming a first cover member 30 that include areflecting material-containing layer 30 a and a light transmitting layer30 b by applying centrifugal force, the reflecting material-containinglayer 30 a formed in the groove of the grooved part 17 being obtained bysettling a first reflecting material in a first resin, and the lighttransmitting layer 30 b covering at least a portion of lateral surfacesof the light emitting element 20; and a light transmitting memberforming process S107 of forming a light transmitting member 50 on thefirst cover member 30 and the light emitting element 20.

The material, location, and the like of each member are as describedwith reference to the light emitting device 100 above, and theexplanation thus will be omitted here as appropriate.

Substrate Providing Process

The substrate providing process S101 comprises providing a substratethat includes a grooved part 17 surrounding a first region 16.

In the process S101, a package 10 is provided that has a recessed part15 defined by an upper surface of a substrate 2 and lateral surfaces ofresin walls 3.

In the process S101, a grooved part 17 that surrounds a first region 16is formed in the first lead electrode 2 a. The grooved part 17 can beformed by, for example, etching or press forming. A plating layer isformed on the surfaces of the first lead electrode 2 a and the secondlead electrode 2 b, as needed, by electroless plating or electroplating.Grooves used in disposing resin walls 3 can be formed in the first leadelectrode 2 a and the second lead electrode 2 b at the same time thegrooved part 17 is formed. After placing the first lead electrode 2 aand the second lead electrode 2 b in a mold for manufacturing a package,a resin for forming resin walls 3 and a resin molded part 2 c isinjected into the mold, and the resin is hardened. In this manner, apackage 10 having a grooved part 17 created in the substrate 2 can bemanufactured.

For the process S101, a substrate with a preformed groove can beprovided.

Light Emitting Element Mounting Process

The light emitting element mounting process S102 comprises mounting alight emitting element 20 in the first region 16.

In the process S102, a light emitting element 20 is mounted on thebottom surface of the recessed part 15 of the package 10. In the presentembodiment, the light emitting element 20 is disposed on the first leadelectrode 2 a. The light emitting element 20 is mounted on the bottomsurface of the recessed part 15 with the electrode formed surface facingup by using a non-conductive bonding material. That is, the electrodeformed surface is used as the primary light extraction surface, and thesurface opposite to the electrode formed surface is used as the mountingsurface. For the non-conductive bonding material, for example, an epoxyresin or silicone resin can be used. The light emitting element 20 canbe flip-chip mounted, and in this case, it is mounted using a conductivebonding material. For the conductive bonding material, for example,eutectic solder, conductive past, bumps, or the like can be used.

Second Cover Member Forming Process

The second cover member forming process S103 comprises forming a secondcover member 40 by allowing a second resin to continuously cover fromthe lateral surfaces of the recessed part 15 to the upper edge of theouter perimeter of the grooved part 17.

In the process S103, a second resin that covers the lateral surfaces ofthe recessed part 15 is disposed by a potting process, for example. Thesecond resin can be disposed in the recessed part 15 by using a resindispenser containing an uncured second resin material such that theuncured resin material is discharged from the nozzle at the tip of thedispenser in the vicinity of the outer edges of the bottom surface ofthe recessed part 15, preferably along the boundaries with the lateralsurfaces. The uncured second resin covers the lateral surfaces of therecessed part 15 by wetting and spreading over thereon. At this time,because the second resin also flows onto the bottom surface of therecessed part 15, the second resin also covers a portion of the bottomsurface of the recessed part 15. At this time, the viscosity and thedispensing positions of the second resin are preferably preadjusted suchthat the second resin flowing onto the bottom surface of the recessedpart 15 would not reach the upper edge of the outer perimeter of thegrooved part 17 and not wet or spread over the grooved part 17, but cancreep up to the upper portions of the lateral surfaces of the recessedpart 15. In the case of forming the second cover member 40 by a pottingprocess, the viscosity of the second resin is adjusted, for example, tobe in a range of 1 Pa·s to 50 Pa·s at room temperature (20±5° C.).

If the second resin flows into the groove of the grooved part 17, itmight run beyond the upper edge of the inner perimeter of the groovedpart 17 while wetting and spreading over the lateral surfaces of thelight emitting element 20. This might hinder the extraction of lightfrom the lateral surfaces of the light emitting element 20. Thus, it ispreferable not to allow the second resin to cover the interior of thegroove of the grooved part 17.

The interior surfaces of the recessed part 15 of the package 10 can bepre-impregnated with an organic solvent. Pre-impregnating the interiorsurfaces of the recessed part 15 with an organic solvent can promote thecreeping of the second resin onto the lateral surfaces of the recessedpart 15. Employing a material having high wettability for the lateralsurfaces of the recessed part 15, or roughening the surfaces thereof,can also facilitate the creeping of the resin onto the lateral surfacesof the recessed part 15.

The second resin before hardening contains a second reflecting material,and the concentration of the second reflecting material in the secondresin is preferably 10 mass percentage to 50 mass percentage.

The second resin wets and spreads over the lateral surfaces of therecessed part 15 when disposed in the vicinity of the outer edges of thebottom surface of the recessed part 15 using a potting process. At thispoint, the second cover member 40 is in the state where the secondreflecting material is dispersed in the second resin.

Subsequently, the second resin is allowed to harden at a temperature of,for example, 120° C. to 200° C. to form the second cover member 40. Thesecond resin is preferably hardened after wetting and spreading over thelateral surfaces of the recessed part 15 and in the condition where thepackage is not moved.

First Resin Forming Process

The first resin forming process S104 comprises mixing a base agent of atwo-part curing-type resin material and a first reflecting material,followed by mixing a hardening agent a predetermined time period.

Using the first resin formed in this manner can enhance the affinitybetween the first reflecting material and the resin material. This canfacilitate the settling of the first reflecting material undercentrifugal force. The temperature prior to mixing the hardening agentis room temperature.

Examples of two-part curing-type resin materials include siliconeresins, modified silicone resins, epoxy resins, modified epoxy resins,and the like.

The time allowed to elapse after mixing the base agent of two-partcuring-type resin material and the first reflecting material ispreferably at least two hours from a perspective of further facilitatingthe settling of the first reflecting material. The time allowed toelapse is preferably eight hours at most from a manufacturing timereduction perspective. After mixing the hardening agent, the subsequentstep is performed before the first resin hardens.

The concentration of the first reflecting material relative to theuncured first resin is, for example, about 15 mass percentage to about60 mass percentage.

First Resin Depositing Process

The first resin depositing process S105 forming a first resin 31 in thegroove of the grooved part 17. The first resin 31 contains a firstreflecting material.

In the process S105, an uncured first resin 31 is disposed between thelateral surfaces of the recessed part 15 and the upper edge of the outerperimeter of the groove 17, for example, by a potting process.Specifically, the uncured first resin 31 is disposed on the second covermember 40 that continuously covers from the lateral surfaces of therecessed part 15 to the upper edge of the outer perimeter of the groovedpart 17. By disposing the first resin on the second cover member 40 inthe vicinity of the grooved part 17, the first resin flows into andformed in the grooved part 17. Preferably, the uncured first resin 31 isdisposed, for example, at two locations near the opposing lateralsurfaces of the light emitting element 20 to be allowed to flow into andbe formed in the groove by its own weight or centrifugal force. This canallow the first resin flowed into the groove to move inside the groovein parallel with the bottom surface of the recessed part 15, to therebyinhibit the first resin from wetting and spreading in the verticaldirection before being formed in the groove.

In other words, potting the first resin 31 not directly in the groovedpart 17 can inhibit the first resin from flowing towards the lightemitting element 20, to thereby inhibit the first resin from creepingonto the lateral surfaces of the light emitting element 20 before beingrotated under centrifugal force. The creeping of the first resin ontothe lateral surfaces of the light emitting element 20 can be avoided asthe shape of the first resin changes after rotating under centrifugalforce. Depending on the viscosity of the first resin and the rotationalspeed, however, the first reflecting material contained in the firstresin might remain on the lateral surfaces of the light emitting element20. Thus, preferably, the first resin does not cover the lateralsurfaces of the light emitting element 20 prior to rotation undercentrifugal force.

In the case in which the first resin does not readily flow inside thegroove because of the viscosity of the resin or the like, the firstresin 31 can be disposed directly in the groove by a potting process orthe like.

First Cover Member Forming Process

The first cover member forming process S106 forms a first cover member30 by applying centrifugal force to the substrate on which the firstresin is disposed at the grooved part 17, to obtain the reflectingmaterial-containing layer 30 a and a light transmitting layer 30 b. Thereflecting material-containing layer 30 a, which contains a firstreflecting material and is disposed in the groove of the grooved part17, can be obtained by settling the first reflecting material containedin the first resin by applying the centrifugal force. The lighttransmitting layer 30 b covers at least some portions of the lateralsurfaces of the light emitting element 20 by the centrifugal force.

In the process S106, the substrate 2, i.e., the package 10, is rotatedunder centrifugal force in the direction that applies the centrifugalforce to the bottom surface of the recessed part 15. Forcibly settlingthe first reflecting material in the first resin towards the bottomsurface of the recessed part 15 under centrifugal force can form thereflecting material-containing layer 30 a containing a highconcentration of the first reflecting material, as a first reflectingmaterial settled layer, and a light transmitting layer 30 b as asupernatant. Forming the reflecting material-containing layer 30 a bycentrifugal settling in this manner can increase the density of thefirst reflecting particles on the bottom surface side even with areduced amount of the first reflecting material contained in the firstresin. In the manner described above, the reflecting material-containinglayer 30 a disposed in the groove of the grooved part 17, and the lighttransmitting layer 30 b covering some portions of the lateral surfacesof the light emitting element 20 can be formed.

In the case of using centrifugal force to allow the first resin to flowinside the groove in the first resin depositing process S105, thecentrifugal force rotation can simultaneously accomplish the centrifugalforce rotation performed in the process S106.

As shown in FIG. 3D, the rotation of the package 10 is preferablyperformed by applying centrifugal force to the package 10 around arotary shaft 90 such that the upper surface of the substrate 2, i.e.,the bottom surface of the recessed part 15, is positioned outward.Specifically, the package 10 is moved in direction A revolving aroundthe rotary shaft 90 that is positioned on the upper surface side of thepackage 10. Direction B in FIG. 3D parallels the bottom surface of therecessed part 15. FIG. 3D, three arrows indicating direction B are shownalong the movement of the package 10, but direction B is continuous inreality.

The rotary shaft 90 is in parallel to the bottom surface of the recessedpart 15 positioned on a line orthogonal to and passing throughsubstantially the center of the bottom surface of the recessed part 15,and is positioned on the open end of the recessed part 15 of the package10. In this manner, centrifugal force is applied in the directiontowards the bottom surface of the recessed part 15, thereby inhibitingthe first resin from spreading in the height direction of the package 10and forcibly settling the first reflecting material contained in thefirst resin towards the bottom surface of the recessed part 15 (i.e., inthe direction indicated by arrow C in FIG. 3D). Allowing the first resinto harden in this state can form the reflecting material-containinglayer 30 a and the light transmitting layer 30 b at the grooved part 17in that order from the bottom surface of the recessed part 15.

For the first cover member 30, the applying amount and the amount of thefirst reflecting material contained in the first resin can be suitablyadjusted.

Although the rotational speed or number of rotations (e.g. rpm) for thepackage 10 would depend on the content, particle diameter, and the likeof the first reflecting material, the number of rotation and rotationradius can be adjusted such that centrifugal force of at least 200×gapplies, for example.

In the manufacturing process, in the case of rotating under centrifugalforce packages 10 configuring as a substrate block before being dividedinto individual packages where the substrate block is a sheet, thelarger the area of the substrate block (more specifically, the longerthe substrate length in the rotation direction A), the larger thedeviations from the rotary shaft 90 result in the packages 10 that aremore distant from the center of the substrate block. In a substrateblock, for example, a large deviation in direction B from the rotationcircumference would cause the first resin surface to become oblique tothe bottom surface of the recessed part 15, possibly resulting invariation in the surface condition of the first resin among the packagesin the substrate block. These deviations can be reduced by increasingthe rotation radius. Specifically, the deviations can be reduced bysetting the rotation radius to at least 70 times the length of thesubstrate block in the rotation direction.

In the case of using resin packages 10 having flexibility where thesubstrate block flexes along the rotation circumference of the turningradius, the packages would be less susceptible to the deviationsdescribed above. Thus, rotation can be performed with a larger substrateblock than in the case of employing a substrate block composed ofnon-flexible packages 10 under the same centrifugal force. This canincrease the number of packages processed each time. Examples offlexible substrates block include resin packages linked with leads.

In the process S106, moreover, the first resin is preferably hardenedwhile settling the first reflecting material, i.e., while applyingcentrifugal force. It is preferable to use a material having a smallparticle diameter for the first reflecting material. However, particleshaving small diameter is difficult to settle. Therefore, the firstreflecting material is forcibly settled towards the bottom surface ofthe recessed part 15 by centrifugal force in the process S106.Accordingly, in order to harden the resin while the first reflectingmaterial is being settled, the process of hardening the first resin ispreferably performed by maintaining the rotation, i.e., while rotatingthe package, in the process S106.

Although the resin can be hardened after ceasing the rotation, the resincan readily spread onto the lateral surfaces of the light emittingelement 20 due to wettability once the rotation ceases. Accordingly,allowing the first resin to harden while rotating the package 10 caninhibit the first resin from creeping onto the lateral surfaces of thelight emitting element 20. Exposing the lateral surfaces of the lightemitting element 20 from the first resin can further improve the lightextraction efficiency and further enhance the light distributioncharacteristics of the light emitting device 100.

The hardening temperature for the first resin can be in a range of 40°C. to 200° C. Setting the hardening temperature high can reduce the timerequired to harden the first resin and is thus efficient. Consideringthe wobbling of the rotary shaft 90 that can occur as a result ofthermal expansion of metal parts of the centrifuge equipment, thehardening temperature is preferably set low to the extent possible. Inother words, the hardening temperature for the first resin from anefficiency perspective is preferably 50° C. or higher. The hardeningtemperature, considering the wobbling of the rotary shaft 90, ispreferably 60° C. at most. In the case of hardening the resin at 80° C.or higher, it is preferable to adjust the equipment such that at leastthe metal parts of the centrifuge equipment will not reach 80° C. orhigher.

For the resin material employed for the first resin, one that canachieve at least a semi-hardened state when the rotating package 10 ismaintained at 40° C. or a higher temperature is preferably selected.

Examples of methods for hardening the first resin while settling thefirst reflecting material include the use of a hot air blower, a panelheater, and the like.

Light Transmitting Member Forming Process

The light transmitting member forming process S107 forms a lighttransmitting member 50 on the first cover member 30, the second covermember 40, and the light emitting element 20.

In the process S107, a resin employed for the light transmitting member50 is disposed in the recessed part 15 by potting, spraying, or thelike. Subsequently, the resin employed for the light transmitting member50 is hardened at a temperature in a range of, for example, 120° C. to200° C. to form the light transmitting member 50.

Although certain embodiments of light emitting devices and methods formanufacturing light emitting devices have been specifically explainedabove, the spirit of the present invention is not limited to thosedescribed above, and must be broadly interpreted based on the disclosuremade in the scope of the claims. Various modifications and variationsmade based on these disclosures are also encompassed by the spirit ofthe present invention.

Other Embodiments

FIG. 4 is a schematic cross-sectional view of a light emitting deviceaccording to another embodiment of the present disclosure. FIG. 5A is aschematic top view of the grooved part of a light emitting deviceaccording to another embodiment. FIG. 5B is a schematic top view of thegrooved part of a light emitting device according to another embodiment.FIG. 5C is a schematic top view of the grooved part of a light emittingdevice according to another embodiment.

The light emitting device 100A shown in FIG. 4 includes a protectivedevice 60. The protective device 60 has an electrode on the uppersurface, and is mounted on the second lead electrode 2 b at the bottomsurface of the recessed part 15 of the package 10 with the electrodeformed surface facing up. In the present embodiment, the electrode ofthe protective element 60 is connected to the first lead electrode 2 avia a conductive member such as a wire 25. The protective device 60, forexample, is a Zener diode.

The protective device 60 can be mounted on the bottom surface of therecessed part 15 of the package 10 in the light emitting mountingprocess S102.

The light emitting device can include a plurality of light emittingelements 20. In the case in which two light emitting elements 20 areincluded, for example, the grooved part 17 can be a quadrilateralannular grooved part 17 that surrounds the two light emitting elements20 in a top view, as shown in FIG. 5A. Alternatively, as shown in FIG.5B, quadrilateral annular grooved parts 17 can be provided toindividually surround the two light emitting elements 20 in a top view.Alternatively, as shown in FIG. 5C, the grooved part 17 can be such thatthe groove between the two light emitting elements 20 is integrallyformed.

The light emitting devices explained in the foregoing are of the typewhere the light emitting elements are mounted with the electrode formedsurface facing up, but light emitting elements can be flip-chip mounted.In the case of employing flip-chip mounting for a light emittingelement, the light emitting element is preferably raised in the heightdirection by using a base, such as a submount, bumps, post electrodes,or the like. When a light emitting element is flip-chip mounted, thesemiconductor layer is disposed on the bottom surface side of therecessed part of the substrate (i.e., the substrate side of the lightemitting device). Raising the light emitting element in the heightdirection can position the lateral surfaces of the semiconductor layerso as not to be covered by the first cover member in whole or in part.

The light emitting devices explained in the foregoing are of the typethat use a package formed with a recess in which a light emittingelement is mounted on the bottom surface thereof. The light emittingdevices, however, can be those that employ a flat substrate on which alight emitting element is mounted.

A method of manufacturing a light emitting element can include anadditional process before, after, or between the processes describedearlier to the extent that the processes described earlier are notadversely affected. For example, a foreign matter removal process toremove foreign matter mixed into during manufacturing, and the like, canbe included.

In a method of manufacturing a light emitting device, moreover, theorder of certain processes is not limited, and can be replaced. Forexample, in the method of manufacturing a light emitting devicedescribed earlier, the first resin forming process followed by thesecond cover member forming process. The first resin forming process,however, can be performed before the second cover member formingprocess, the light emitting element mounting process, or the substrateproviding process. Alternatively, the method can be adapted to excludethe first resin forming process.

The second cover member forming process has been explained as beingperformed after the light emitting element mounting process, but beforethe first resin forming process. The second cover member formingprocess, however, can be performed before the light emitting elementmounting step, or performed after the first cover member formingprocess, but before the light transmitting member forming process.

EXAMPLES

Examples of the present invention will be explained below.

FIG. 6 shows images of the structures of the light emitting devices usedin Example 1. FIG. 7A is a graph showing the relationship between thefirst resin applying amount and the luminous flux in Example 1. FIG. 7Bis a graph showing x chromaticity coordinate deviations directivityangle directivity angles in Example 1. FIG. 7C is a graph showing ychromaticity coordinate deviations directivity angle directivity anglesin Example 1. FIG. 7D is a graph showing x chromaticity coordinatedeviations directivity angle directivity angles in Example 1. FIG. 7E isa graph showing y chromaticity coordinate deviations directivity angledirectivity angles in Example 1. FIG. 8A is an image of a light emittingdevice of Example 2 showing the state after mounting a light emittingelement and applying a second resin. FIG. 8B is an image of the lightemitting device of Example 2 showing the state after applying a firstresin. FIG. 8C is an image of the light emitting device of Example 2showing the state after settling the reflecting material by applyingcentrifugal force to the first resin. FIG. 8D is an image of electrodesof the light emitting element in the light emitting device of Example 2.FIG. 8E is an image of the light emitting device of Example 2 showingthe state after forming a light transmitting member. FIG. 9A is a graphshowing the relationship between the chromaticity coordinate and theluminous flux in Example 2. FIG. 9B is a graph showing the luminous fluxof each sample in Example 2.

Example 1

The light emitting devices structured as shown in FIG. 6 were produced.The light emitting devices having the structures shown in FIG. 6 weresubstantially the same except for varying the amount of the first resinapplied. Packages each having a grooved part formed at the bottomsurface of the recessed part were provided. In each package a first leadelectrode and a second lead electrode were provided at the bottomsurface of the recessed part, and the grooved part was formed in thefirst lead electrode. The lead electrodes were Au plated. The groovedpart had a substantially semicircular cross section, 100 μm in width and100 μm in depth.

Then a light emitting element was mounted on the bottom surface of therecessed part. Then a second cover member was formed using a secondresin containing a second reflecting material to cover the bottomsurface and the lateral surfaces of the recessed part. Then in eachsample of Example 1, a first cover member was formed by supplying afirst resin containing a first reflecting material the groove of thegrooved part and hardening the resin after allowing the first reflectingmaterial to settle by centrifugal settling. The applying amounts of thefirst resin were, as shown in FIG. 6 and FIGS. 7A to 7E, 0.10 mg, 0.12mg, 0.14 mg, and 0.16 mg. Two points were used as the applicationpositions D. The numerical values in the legends in FIGS. 7B to 7Erepresent the applying amounts of the first resin. The concentration ofthe first reflecting material contained in the first resin was 37.5 masspercentage. No first cover member was disposed in the comparativesample. Subsequently, a light transmitting member containing a phosphorwas formed on the first cover member, the second cover member, and thelight emitting element.

For the light emitting elements, nitride-based semiconductor elementshaving a peak emission wavelength of 442 nm were used. For the firstreflecting material, titanium oxide having an average particle diameterof about 280 nm was used, and for the second reflecting material,titanium oxide having an average particle diameter of about 500 nm wasused. For the phosphor, a YAG:Ce was used. For the first resin, asilicone resin having a resin viscosity of 3.5 Pa·s was used, for thesecond resin, a silicone resin having a resin viscosity of 1.0 Pa·s wasused, and for the resin employed to form the light transmitting member,a silicone resin having a resin viscosity of 3.5 Pa·s similar to thefirst resin was used.

The luminous flux of each sample produced as above was measured atchromaticity coordinate of x=0.32. The luminous flux was measured byusing a total luminous flux measurement system that utilizes anintegrating sphere, and a relative luminous flux of each sample wascalculated with the luminous flux of the comparative sample assumed as100%. FIG. 7A shows the results. As shown in FIG. 7A, the samples havingthe first cover member in the groove of the grooved part exhibitedhigher luminous flux than the sample that did not have a first covermember in the groove of the grooved part. Moreover, as compared to thosemade by forming a first cover member without creating a grooved part, inthe samples of Example 1, the first resin is less likely to flow towardsthe light emitting element before settling the first reflectingmaterial. This can simplify manufacturing operations, and improveproduction efficiency.

As a reference, for each sample, x and y chromaticity coordinatedeviations at certain directivity angles were measured. FIG. 7B and FIG.7C show Δx and Δy, respectively, in the case of a directivity angleusing the direction orthogonal to line IC-IC in FIG. 1A (0° direction)as a reference. FIG. 7D and FIG. 7E show Δx and Δy, respectively, in thecase of a directivity angle using line IC-IC in FIG. 1A (90° direction)as a reference. In the present example, the light distributionchromaticity Δx and Δy represent the chromaticity coordinate deviationsat certain directivity angles of the light emitting device using thechromaticity coordinates in the frontal direction as a reference. Asshown in FIGS. 7B to 7E, no notable differences in the lightdistribution chromaticity Δx and Δy were found among the samples havinga first cover member disposed in the groove of the grooved part ascompared to the comparative sample.

In other words, in each sample of Example 1, because the reflectingmaterial-containing layer is formed in the groove while exposing thelateral surfaces of the light emitting element substantially entirely,light extraction from the lateral surfaces of the light emitting elementis not hindered. This can increase only the luminous flux withsubstantially no degradation of the light distribution chromaticity.

Example 2

Light emitting device samples were produced in accordance with themethod used to manufacture the light emitting devices of Example 1. InExample 2, nine samples in which the first reflecting material wassettled by centrifugal settling using equipment I at 700 rpm (rotationradius 0.65 m), and nine samples in which the first reflecting materialwas settled by using equipment II at 3000 rpm (rotation radius 0.1 m)were produced. The applying amount of the first resin was 0.09 mg ineach sample. As comparative samples, nine samples that had no firstcover member in the groove of the grooved part (no centrifugal settling)were produced. FIGS. 8A to 8E are images of a sample made by usingequipment I taken after each manufacturing process.

For each sample, the relationship between the color and the luminousflux was investigated. The luminous flux was measured by using a totalluminous flux measurement system using an integrating sphere at roomtemperature of about 25° C. FIG. 9A shows the results. From the resultsshown in FIG. 9A, the luminous flux at chromaticity coordinate of x=0.32was calculated. FIG. 9B shows the results. As shown in FIG. 9B, thesamples having a first cover member disposed in the groove of thegrooved part exhibited higher luminous flux as compared to the sampleshaving no first cover member in the groove of the grooved part.Moreover, the samples made by using equipment II having a highercentrifugal force than equipment I exhibited higher luminous flux.

Light emitting devices according to embodiments of the presentdisclosure can be utilized as backlight light sources for liquid crystaldisplays, in various lighting fixtures, large displays, various displaydevices such as billboards and destination signs, image readers used indevices, such as digital video cameras, facsimiles, copiers, andscanners, and projectors.

What is claimed is:
 1. A light emitting device comprising: a substrateincluding a grooved part surrounding a first region; a light emittingelement mounted in the first region; a first cover member comprising: areflecting material-containing layer that is disposed in the groove ofthe grooved part and that contains a first reflecting material, and alight transmitting layer that directly contacts a first portion oflateral surfaces of the light emitting element; and a light transmittingmember that is disposed on the first cover member and the light emittingelement and that directly contacts a second portion of the lateralsurfaces of the light emitting element.
 2. The light emitting deviceaccording to claim 1, comprising: a package comprising the substrate, aplurality of resin walls, and a recessed part defined by an uppersurface of the substrate and lateral surfaces of the plurality of resinwalls; and a second cover member containing a second reflecting materialand directly contacting the upper surface of the substrate in a regionthat extends from the lateral surfaces of the plurality of resin wallsto an upper edge of an outer perimeter of the grooved part.
 3. The lightemitting device according to claim 2, wherein the first cover memberdirectly contacts an upper surface of the second cover member.
 4. Thelight emitting device according to claim 3, wherein the upper surface ofthe second cover member is inclined so as to extend upward and outwardfrom the upper edge of the outer perimeter of the grooved part.
 5. Thelight emitting device according to claim 1, wherein a width of thegrooved part is in a range of 30 μm to 200 μm.
 6. The light emittingdevice according to claim 1, wherein a depth of the grooved part is in arange of 10 μm to 150 μm.
 7. The light emitting device according toclaim 1, wherein the grooved part is formed at a position that is 100 μmor less from the light emitting element.
 8. The light emitting deviceaccording to claim 1, wherein the light transmitting member contains awavelength conversion material.
 9. The light emitting device accordingto claim 1, wherein an upper surface of the first covering member isinclined so as to extend downward and outward from the first portion ofthe lateral surfaces of the light emitting element.
 10. The lightemitting device according to claim 1, wherein the substrate comprises afirst lead electrode, a second lead electrode, and a resin molded partthat supports the first lead electrode and the second lead electrode.11. The light emitting device according to claim 10, wherein the groovedpart is located at an upper surface of the first lead electrode.
 12. Thelight emitting device according to claim 10, further comprising: aprotective device; wherein the light emitting element is mounted on thefirst lead electrode, and the protective device is mounted on the secondlead electrode.
 13. The light emitting device according to claim 1,wherein the light emitting element is offset from a center of thesubstrate.
 14. A method of manufacturing a light emitting device, themethod comprising: providing a substrate that includes a grooved partsurrounding a first region; mounting a light emitting element in thefirst region; depositing a first resin in or adjacent to a groove of thegrooved part, the first resin containing a first reflecting material;forming a first cover member, which comprises applying centrifugal forceto the substrate and the first resin that is deposited in or adjacent tothe groove of the grooved part, so as to form the first cover membercomprising: a reflecting material-containing layer formed in the grooveof the grooved part by settling the first reflecting material in thefirst resin, and a light transmitting layer that directly contacts afirst portion of lateral surfaces of the light emitting element; andforming a light transmitting member on the first cover member and thelight emitting element such that the light transmitting member directlycontacts a second portion of the lateral surfaces of the light emittingelement.
 15. The method of manufacturing a light emitting deviceaccording to claim 14, wherein: the step of providing the substratecomprises providing a package that comprises the substrate, a pluralityof resin walls, and a recessed part defined by an upper surface of thesubstrate and lateral surfaces of the plurality of resin walls; and themethod further comprises, before the step of depositing the first resin,forming a second cover member that contains a second reflecting materialand directly contacts the upper surface of the substrate in a regionthat extends from the lateral surfaces of the plurality of resin wallsto an upper edge of an outer perimeter of the grooved part.
 16. Themethod of manufacturing a light emitting device according to claim 14,wherein the step of forming the first cover member comprises hardeningthe first resin under the centrifugal force.
 17. The method ofmanufacturing a light emitting device according to claim 16, wherein atemperature used for hardening the first resin is in a range of 40° C.to 200° C.
 18. The method of manufacturing a light emitting deviceaccording to claim 14, wherein a viscosity of the first resin is in arange of 0.3 Pa·s to 15 Pa·s.
 19. The method of manufacturing a lightemitting device according to claim 14, further comprising providing afirst resin before the step of depositing the first resin, forming thefirst resin, which comprises mixing a base agent of a two-part hardeningtype resin material and the first reflecting material to form a mixture,and after the passage of at least two hours, mixing a hardening agentinto the mixture.
 20. The method of manufacturing a light emittingdevice according to claim 14, wherein the light transmitting membercontains a wavelength conversion material.